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  • 1995-1999  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Measurements of aerobic metabolism of a school of horse mackerel at different swimming speeds (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 49 (1996), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Oxygen consumption rates were measured in a school of 56 horse mackerel Trachurus trachurus while at rest and while swimming at steady sustained speeds. Resting values of 38.76 and 42.10mg O2 kg−1 h−1 were measured in a sealed cylindrical tank (535 l) while observing that the fish school remained neutrally buoyant and inactive with only gentle pectoral fin movements and no swimming motion. The same school was trained to swim with projected light patterns within a 10-m diameter annular doughnut respirometer. The oxygen consumption increased from the resting level through 51 mg O2 kg−1 h−1 at the slowest swimming speeds of 0.29 m s−1 (0.95 L s−1) to around 259 mg O2 kg−1 h−1 at the higher measured swimming speed of 0.87 m s−1 (2.82 L s−1). The data fitted a curve where oxygen consumption rose in proportion to velocity to the power of 2.56 with the intercept at the resting level. The maximum sustained speed (80 min) of 1.12 m s−1 (3.63 Ls−1) was not achieved within the respirometer but corresponded to an estimated oxygen consumption of 458.33 mg O2 kg−1 h−1 giving a scope for aerobic activity of 419.02 mg O2 kg−1 h−1. At a speed of 0.87 m s−1, there was a lower bound on the aerobic efficiency of at least 38% and at 1.12 m s−1, the highest aerobic speed, of 40%. Sustained speeds swum in a curved path as here should be increased by 5% for a straight path giving a maximum sustained 80 min speed of 1.18 m s−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1996.tb00084.x
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Upstream migration of adult Atlantic salmon past a fish counter weir in the Aberdeenshire Dee, Scotland (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 51 (1997), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: During their upstream migration through the lower reaches of the Aberdeenshire Dee, Scotland, radio-tagged adult Atlantic salmon passed a Crump weir-based fish counter without substantial delay over a range of river flows and water temperatures. Tagged salmon were detected sequentially by automatic listening stations placed along the river and were detected at the counter site for a median time of 18 min, compared with a median time of 5 min before the weir was built. One fish out of 16 spent 6·7 h in the vicinity of the weir, but such migratory pauses also occurred before the weir existed. The results suggest that the number of salmon crossing the counter per unit time is a function of the number of fish present downstream and their tendency to migrate upstream, without being limited by their ability to surmount the weir. The apparent slight delay at the weir is probably insignificant in terms of the overall progress of riverine migration and in the context of using counter records to relate salmon movements to environmental Variables.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1997.tb01664.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    PEACE: A PLASMA ELECTRON AND CURRENT EXPERIMENT (1997)
    Springer
    Space science reviews 79 (1997), S. 351-398 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An electron analyser to measure the three-dimensional velocity distribution of electrons in the energy range from 0.59 eV to 26.4 keV on the four spacecraft of the Cluster mission is described. The instrument consists of two sensors with hemispherical electrostatic energy analysers with a position-sensitive microchannel plate detectors placed to view radially on opposite sides of the spacecraft. The intrinsic energy resolutions of the two sensors are 12.7% and 16.5% full width at half maximum. Their angular resolutions are 2.8° and 5.3° respectively in an azimuthal direction and 15° in a polar direction. The two sensors will normally measure in different overlapping energy ranges and will scan the distribution in half a spacecraft rotation or 2 s in the overlapped range. While this is the fastest time resolution for complete distributions, partial distributions can be recorded in as little as 62.5 ms and angular distributions at a fixed energy in 7.8 ms. The dynamic range of the instrument is sufficient to provide accurate measurements of the main known populations from the tail lobe to the plasmasheet and the solar wind. While the basic structure of the instrument is conventional, special attention has been paid in the design to improving the precision of the instrument so that a relative accuracy of the order of 1% could be attained in flight in order to measure the gradients between the four spacecraft accurately; to decreasing the minimum energy covered by this technique from 10 eV down to 1 eV; and to providing good three dimensional distributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004938001388
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    The Toroidal Imaging Mass-Angle Spectrograph (TIMAS) for the polar mission (1995)
    Springer
    Space science reviews 71 (1995), S. 497-530 
    Details
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The science objectives of the Toroidal Imaging Mass-Angle Spectrograph (TIMAS) are to investigate the transfer of solar wind energy and momentum to the magnetosphere, the interaction between the magnetosphere and the ionosphere, the transport processes that distribute plasma and energy throughout the magnetosphere, and the interactions that occur as plasma of different origins and histories mix and interact. In order to meet these objectives the TIMAS instrument measures virtually the full three-dimensional velocity distribution functions of all major magnetospheric ion species with one-half spin period time resolution. The TIMAS is a first-order double focusing (angle and energy), imaging spectrograph that simultaneously measures all mass per charge components from 1 AMU e−1 to greater than 32 AMU e−1 over a nearly 360° by 10° instantaneous field-of-view. Mass per charge is dispersed radially on an annular microchannel plate detector and the azimuthal position on the detector is a map of the instantaneous 360° field of view. With the rotation of the spacecraft, the TIMAS sweeps out very nearly a 4π solid angle image in a half spin period. The energy per charge range from 15 eV e−1 to 32 keV e−1 is covered in 28 non-contiguous steps spaced approximately logarithmically with adjacent steps separated by about 30%. Each energy step is sampled for approximately 20 ms;14 step (odd or even) energy sweeps are completed 16 times per spin. In order to handle the large volume of data within the telemetry limitations the distributions are compressed to varying degrees in angle and energy, log-count compressed and then further compressed by a lossless technique. This data processing task is supported by two SA3300 microprocessors. The voltages (up to 5 kV) for the tandem toroidal electrostatic analyzers and preacceleration sections are supplied from fixed high voltage supplies using optically controlled series-shunt regulators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00751339
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    Paper (German National Licenses)
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